Scan Rules (Advanced)

Scan Rules are boolean expressions used to decide whether a symbol matches. The advanced editor uses CEL-style syntax.

Syntax

Use comparisons and boolean logic. Expressions must evaluate to true or false.

// Comparison
rsi_14 < 30
close > ma_50

// Boolean logic
has_rsi_14 && has_ma_50 && rsi_14 < 30 && close > ma_50
(close > open) || (daily_move_pct > 5)

// Perp-only example
contract_type == "perp" && has_funding_rate && funding_rate > 0.001

Guard Pattern (Recommended)

For optional metrics, always check the matching has_* flag first. This prevents per-symbol evaluation failures on missing data.

// Good
has_rsi_14 && has_ma_50 && rsi_14 < 30 && close > ma_50

// Risky (no guards)
rsi_14 < 30 && close > ma_50

Price Alert Examples

Price alerts are regular scan rules built from symbol plus a price field such as close. In the Builder, the market selector usually handles spot vs perp for you, but you can make the contract explicit in Advanced mode when needed.

// BTCUSDT above a price on Binance spot
symbol == "BTCUSDT" && contract_type == "spot" && close >= 100000.0

// BTCUSDT below a price on Binance perpetuals
symbol == "BTCUSDT" && contract_type == "perp" && close <= 95000.0

// ETHUSDT below a price on Binance spot
symbol == "ETHUSDT" && contract_type == "spot" && close <= 2500.0

If you already set the scan Market Type to spot or perp, the extra contract_type check is optional and mostly useful for documentation clarity.

Supported Variables

Source of truth: GET /api/crypto/scans/variables?contract_type=spot or GET /api/crypto/scans/variables?contract_type=perp.

Price

close, open, high, low

Indicators

rsi_14, rsi_20, ma_20, ma_50, ma_200, rsi_14_normalized

Volume

volume_quote, volume_base

Derived

daily_move_pct, above_ma50, below_ma50, above_ma200, below_ma200, close_to_ma50, close_to_ma200, bullish_trend, bearish_trend

Previous Candle

prev_close, prev_open, prev_high, prev_low, prev_rsi_14, prev_rsi_20, prev_ma_50, prev_ma_200, prev_volume_quote, prev_volume_base

Deltas

delta_close, delta_rsi_14, delta_volume_quote

Metadata

symbol, exchange, contract_type

Safety Flags

has_open, has_high, has_low, has_volume_quote, has_volume_base, has_rsi_14, has_rsi_20, has_ma_20, has_ma_50, has_ma_200, has_prev_close, has_prev_rsi_14, has_prev_rsi_20, has_prev_ma_50, has_prev_ma_200, has_prev_volume_quote, has_prev_volume_base, has_delta_close, has_delta_rsi_14, has_delta_volume_quote, has_funding_rate, has_mark_premium

Perp-only

funding_rate, mark_premium

Validation Rules

Expression must return boolean
Max length and AST complexity limits are enforced
Banned functions: matches(), split(), join()
Validation warnings are returned for likely missing guards